a. Field of the Invention
The instant invention relates to catheters. In particular, the instant invention relates to a catheter with a steerable distal section having reduced variation in planarity during deflection.
b. Background Art
It is well-known that the pumping action of the heart is controlled by electrical stimulation of myocardial tissue. Stimulation of this tissue in various regions of the heart is controlled by a series of conduction pathways contained within the myocardial tissue.
Cardiac arrhythmias arise when the pattern of the heartbeat is changed by abnormal impulse initiation or conduction in the myocardial tissue. Such disturbances often arise from additional conduction pathways which are present within the heart either from a congenital developmental abnormality or an acquired abnormality which changes the structure of the cardiac tissue, such as a myocardial infarction.
One of the ways to treat such disturbances is to identify the conductive pathways and to sever part of this pathway by destroying these cells which make up a portion of the pathway. Traditionally, this has been done by either cutting the pathway surgically; freezing the tissue, thus destroying the cellular membranes; or by heating the cells, thus denaturing the cellular proteins. The resulting destruction of the cells eliminates their electrical conductivity, thus destroying, or ablating, a certain portion of the pathway. By eliminating a portion of the pathway, the pathway may no longer maintain the ability to conduct, and the arrhythmia ceases.
The success and advancement of current therapies is dependent upon the development and use of more precise localization techniques which allow accurate anatomical determination of abnormal conductive pathways and other arrythmogenic sites. Historically, the electrophysiologist has had to compromise between placing the catheter in the place of greatest clinical interest and areas that are anatomically accessible.
One area of advancement in improving localization techniques and accessing additional sites includes the use of curved and steerable catheters. Curved catheters offer improved maneuverability to specific, otherwise inaccessible sites by being shaped specifically to access a particular site. Although perhaps useful for some more accessible sites, the use of this type of catheter has limitations in reaching sites requiring active articulation during placement. Steerable catheters, which may also be pre-curved, proved additional advantages.
While steerability of catheters has improved, there is a need to eliminate significant variations in planarity during deflection of the distal tips of catheters. In accordance with this invention, a catheter is provided that addresses and potentially eliminates significant variation in planarity during catheter tip deflection. The invention also offers a catheter capable of a multitude of angular shaft deflection trajectories through a two or three dimensional range including a catheter that could initially be straight and, upon complete deflection, turn into a loop-shaped catheter. This invention would improve product reliability, consistency, and performance, as well as improve safety of electrophysiology ablation or diagnostic procedures.